39 resultados para Species Identification
Resumo:
The development of a quick PCR-based method to distinguish European cryptic Myotis spp., Myotis mystacinus, Myotis brandtii and Myotis alcathoe is described. Primers were designed around species-specific single nucleotide polymorphisms (SNP's) in the ND1 mitochondrial gene, and a pair of control primers was designed in the 12S mitochondrial gene. A multiplex of seven primer combinations produces clear species-specific bands using gel electrophoresis. Robustness of the method was tested on 33 M. mystacinus, 16 M. brandtii and 15 M. alcathoe samples from across the European range of these species. The method worked well on faecal samples collected from maternity roosts of M. mystacinus. The test is intended to aid collection of data on these species through a rapid and easy identification method with the ability to use DNA obtained from a range of sources including faecal matter.
Resumo:
European Regulation 1169/2011 requires producers of foods that contain refined vegetable oils to label the oil types. A novel rapid and staged methodology has been developed for the first time to identify common oil species in oil blends. The qualitative method consists of a combination of a Fourier Transform Infrared (FTIR) spectroscopy to profile the oils and fatty acid chromatographic analysis to confirm the composition of the oils when required. Calibration models and specific classification criteria were developed and all data were fused into a simple decision-making system. The single lab validation of the method demonstrated the very good performance (96% correct classification, 100% specificity, 4% false positive rate). Only a small fraction of the samples needed to be confirmed with the majority of oils identified rapidly using only the spectroscopic procedure. The results demonstrate the huge potential of the methodology for a wide range of oil authenticity work.
Resumo:
Introduction and Aims: The identification of complex chronic polymicrobial infections, such as those observed in the cystic fibrosis (CF) airways, are often a diagnostic challenge. Few studies have compared culture-dependent methods with molecular identification making it hard to describe bacterial communities in a comprehensive manner. The aim of the study is to compare four different methods with respect to their similarities and differences in detection of bacteria. Methods: We compared41 sputum samples fromroutine clinical-culture, extended-culture (aerobic and anaerobic), and molecular identification such as Roche 454-FLX Titanium and T-RFLP to assess concurrence between methodologies in detecting bacteria. The agreement between methodologies in detecting either absence or presence of bacterial taxa was assessed by Kappa (κ) statistics. Results: The majority of bacterial taxa identified by culture were also identified with molecular analysis. In total 2, 60, 25, and 179 different bacterial taxa were identified with clinical-culture, extended-culture, T-RFLP and 454-FLX respectively. Clinical-culture, extended-culture and T-RFLP were poor predictors of species richness when compared to 454-FLX (p < 0.0001). Agreement between methods for detecting Pseudomonas sp. and Burkholderia sp. was good with κ ≥ 0.7 [p < 0.0001] and κ ≥ 0.9 [p < 0.0001] respectively. Detection of anaerobic bacteria, such as Prevotella sp. and Veillonella sp., was moderate between extended-culture and 454-FLX with κ = 0.461 [p < 0.0001] and κ = 0.311 [p = 0.032] respectively, and good between T-RFLP and 454-FLX with κ = 0.577 [p < 0.0001] and κ = 0.808 [p < 0.0001] respectively. Agreement between methods for other main bacterial taxa, such as Staphylcoccus sp. and Streptococcus sp., was poor with only a moderate agreement for detection of Streptococcus sp. observed between T-RFLP and 454-FLX (κ = 0.221 [p = 0.024]). Conclusions: This study demonstrates the increased sensitivity culture-independent microbial identification such as the 454-FLX have over clinical-culture, extended-culture and T-RFLP methodologies. The extended-culture detected majority of the most prevalent bacterial taxa associated with chronic colonisation of the CF airways which were also detected by culture-independent methodologies. However, agreement between methods in detecting number of potentially relevant bacteria is largely lacking.
Resumo:
Fragments of chelonian carapace and plastral dermal plates are well-represented from archaeological sites in the world's dry and wet tropics. However, although these bones are easily identified at an element level, few archaeological reports have explored the potential of using features of form and surface sculpturing as a way to refine that identification to genus or species. The ability to achieve such a refinement would benefit environmental and human subsistence strategy models alike. The objective of the current paper was to isolate recurrent and readily visible surface characteristics on the dermal plates from a selection of commonly occurring Southeast Asian hard- and soft-shelled turtles. Using these criteria, analysis is made of the chelonian assemblage from pre- and post-Last Glacial Maximum (LGM) cultural deposits in the West Mouth of Niah Cave. Copyright (C) 2009 John Wiley & Sons, Ltd.
Resumo:
Evidence for osseous technologies has featured in excavation reports from Southeast Asia for almost a century and from archaeological deposits as old as 43,000 years BP. However, in contrast to the significance that is placed on this technology in other parts of the world, until recently, Southeast Asian assemblages have drawn only very limited attention. Concentrating on evidence from Malaysia, the current paper examines one element of this inventory of tools: the deliberate modification of pig canines and the means by which such alteration can be distinguished from patterns of natural tooth wear. Particular attention is paid to the bearded pig (Sus barbatus), as it is one of the two species of wild boar in Malaysia whose tusks are most likely to have been used by prehistoric toolmakers. Reference is also made to wider, regional ethnographic examples of known tusk implements and their accredited uses to further assist in the identification process. Distinguishing criteria for worked tusk are formulated according to the type and extent of modification. These criteria are then applied to archaeological specimens recovered from two prehistoric cave sites in Malaysia, Gua Bintong and Niah Cave.
Resumo:
Burkholderia cenocepacia and other members of the Burkholderia cepacia complex (Bcc) are highly multidrug-resistant bacteria that cause severe pulmonary infections in patients with cystic fibrosis. A screen of 2686 compounds derived from marine organisms identified molecules that could synergize with polymyxin B to inhibit growth of B. cenocepacia. At 1 μg/ml, five compounds synergized with polymyxin B and inhibited the growth of B. cenocepacia by more than 70% compared to growth in polymyxin B alone. Follow-up testing revealed that one compound from the screen, the aminocoumarin antibiotic novobiocin, synergized with polymyxin B and colistin against tobramycin-resistant clinical isolates of B. cenocepacia and Burkholderia multivorans. In parallel, we show that novobiocin sensitivity is common among Bcc species and these bacteria are even more susceptible to an alternative aminocoumarin, clorobiocin, which also had an additive effect with polymyxin B against B. cenocepacia. These studies support using aminocoumarin antibiotics to treat Bcc infections and show that synergizers can be found to increase the efficacy of antimicrobial peptides and polymyxins against Bcc bacteria.
Resumo:
Recent studies predict elevated and accelerating rates of species extinctions over the 21st century, due to climate change and habitat loss. Considering that such primary species loss may initiate cascades of secondary extinctions and push systems towards critical tipping points, we urgently need to increase our understanding of if certain sequences of species extinctions can be expected to be more devastating than others Most theoretical studies addressing this question have used a topological (non-dynamical) approach to analyse the probability that food webs will collapse, below a fixed threshold value in species richness, when subjected to different sequences of species loss. Typically, these studies have neither considered the possibility of dynamical responses of species, nor that conclusions may depend on the value of the collapse threshold. Here we analyse how sensitive conclusions on the importance of different species are to the threshold value of food web collapse. Using dynamical simulations, where we expose model food webs to a range of extinction sequences, we evaluate the reliability of the most frequently used index, R<inf>50</inf>, as a measure of food web robustness. In general, we find that R<inf>50</inf> is a reliable measure and that identification of destructive deletion sequences is fairly robust, within a moderate range of collapse thresholds. At the same time, however, focusing on R<inf>50</inf> only hides a lot of interesting information on the disassembly process and can, in some cases, lead to incorrect conclusions on the relative importance of species in food webs.
Resumo:
Two species of caridean shrimps are newly recorded from hydrothermal vents on the Manus Basin, southwestern Pacific, at depths of 1540-1577m. Lebbeus manus, new species, is related to L.curvirostris Zarenkov, 1976, L.elegans Komai, Hayashi & Kohtsuka, 2004, L.longipes (Kobjakova, 1936), L.vicinus vicinus (Rathbun, 1902) and L.vicinus motereyensis (Wicksten & Mendez, 1982) because of the lack of strap-like epipods on the second and third pereopods; but characters of the rostrum, carapace and abdomen immediately distinguish the new species from the these five taxa. Subadult and juvenile specimens of Nematocarcinus are referred to N.sp.aff.exilis, but their definite identification is postponed until additional specimens become available for study. There are a few minor differences between the present Manus specimens and European specimens representing N.exilis (Bate, 1888), suggesting that the Manus population may indeed represent a separate species.
Resumo:
The chemical compounds synthesised and secreted from the dermal glands of amphibian have diverse bioactivities that play key roles in the hosts' innate immune system and in causing diverse pharmacological effects in predators that may ingest the defensive skin secretions. As new biotechnological methods have developed, increasing numbers of novel peptides with novel activities have been discovered from this source of natural compounds. In this study, a number of defensive skin secretion peptide sequences were obtained from the European edible frog, P. kl. esculentus, using a 'shotgun' cloning technique developed previously within our laboratory. Some of these sequences have been previously reported but had either obtained from other species or were isolated using different methods. Two new skin peptides are described here for the first time. Esculentin-2c and Brevinin-2Tbe belong to the Esculentin-2 and Brevinin-2 families, respectively, and both are very similar to their respective analogues but with a few amino acid differences. Further, [Asn-3, Lys-6, Phe-13] 3-14-bombesin isolated previously from the skin of the marsh frog, Rana ridibunda, was identified here in the skin of P. kl. esculentus. Studies such as this can provide a rapid elucidation of peptide and corresponding DNA sequences from unstudied species of frogs and can rapidly provide a basis for related scientific studies such as those involved in systematic or the evolution of a large diverse gene family and usage by biomedical researchers as a source of potential novel drug leads or pharmacological agents.